This CL removes the parsing of a `-` in front of numerics when lexed.
This will cause the number to become a UnaryOperator negation then the
number instead of a negative number.
Bug: tint:1679, tint:1141, tint:1570
Change-Id: I217c0ffcbe5be934c8d56bd83141b47ade83bc60
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/106463
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>